Equipped with a motorized driven member, an electric toothbrush is becoming popular in the present time, and many kinds of electric toothbrushes have been already on the market. Generally, the electric toothbrush of the prior art comprises a motor provided in a housing inside the handle and a transmission mechanism coupled with the shaft of motor. With the rotation of the motor, the transmission mechanism can drive the brush head. However, a gear driver system is usually applied to be a transmission mechanism. For example, U.S. Pat. No. 5,794,296 disclosed such a constitution, as shown in FIG. 1. Gear box 12 is provided as to be a transmission mechanism, that is, a master gear 18 is fixed on the shaft of motor 14; a equipment gear 20 is coupled with an axis 22 of brush head 16. However, the structure of such meshed gears is not only complex but inefficient as well. Further, the brush head 16 and its method of rotary is not as the same as that of the traditional brush tooth, thus user will feel inconvenient while using it.
FIG. 2 is another brush head of an electric brush tooth 2 of the prior art. Although plenty of groups of brush 22 are arranged on the head 24, the area for arranging the brush 22 is small, as the kind of brush head 24 has to clean the teeth one by one. Definitely, the turning angle of the head 24 and the area covered by the brush will determine whether the kind of electric brush tooth of the prior art can super clean the teeth. However, the turning angle for most of the electric brush of the prior art is very limited, generally less than 180 degrees. Furthermore, when the motor rotates 3 turns, the head 24 can be driven to make 1 cycle motion, so it is difficult to achieve the requirement of energy saving because of its inefficiency.
Summary of the Present Invention
An object of the present invention is to provide an electronic tooth brush having a cam mechanism and a crank mechanism inside a handle to achieve the rotary of the brush head.
Another object of the present invention is to provide an electric brush tooth in which the brush head is arranged eccentrically for super cleaning the teeth.
Another object of the present invention is to provide an electric brush tooth in which the brush head is arranged as an incline for super cleaning the teeth.
The toothbrush of the present invention overcomes the disadvantages of conventional transmission mechanism of electric toothbrush by providing a cam mechanism and a crank mechanism in the handle of the present toothbrush. The cam mechanism of the present invention comprise a cam, mounted on a rotary shaft of a motor via a frame; and a slave unit making a reciprocating movement, defined within the handle and engaged with the cam. The crank mechanism of the present invention comprises a crank, mounted concentrically with the brush head; a link rod, jointed with the crank; and a block, defined within the brush body and engaged with the slave unit. A push spring is provided inside the brush body for pressing against the block. An extension spring is provided on the link rod for going through a dead center of the near-end of the crank mechanism. Alternatively, the block is defined as an uneven shape so that an unbalance pressure can act on it to make the link rod go through a dead center of near-end easily. The cam is a cylindrical cam and is respectively provided with two wave crests and two wave hollows that are fixed with the frame. At least one of the wave hollows is provided to depart a pre-determined distance from the frame for going through the dead center of the far-end of the crank mechanism. Furthermore, the link rod of the crank mechanism may be integrated with the slave unit of said cam mechanism. The present invention preferably arranges several groups of brush to be star shape in order to increase the covered area for super cleaning the teeth and the present invention can also super clean the teeth by inclining the surface of the brush head.
In accordance with an aspect of the present invention, the structure of electric brush tooth is simplified as the cam mechanism is cooperated with the crank, thus its cost can be reduced accordingly. Meanwhile, abrasion of the transmission mechanism is less down.
In accordance with another aspect of the present invention, the present invention achieves energy saving and protects the environment against pollution.
In accordance with another aspect of the present invention, the brush head of the present invention formed star shape not only improves the area of contact for super cleaning but also remains space to be convenient for removing the deposit on the teeth.